Chondrules are dense, mm-scale, igneous spherules that comprise 20-80% of the volume of nearly all of their eponymous meteorite type, the chondrites [1]}, [2]}. Since \(\sim \) 90% of all meteorites in our collections are chondrites, there is a common opinion that chondrules are abundant in primitive asteroids and in the early Solar System [3]}. They are often referred to in text books as the `building blocks' of terrestrial planets and could play an important role in that process [4]}. It is disappointing, therefore, that despite decades of concerted effort and an abundance of fine detail, there remains no consensus among cosmochemists on how they formed [5]}, [6]}, [2]}, [8]}. Their textures indicate that they were born in one or more short blasts of heat, lasting only minutes to hours, but intense enough to melt pre-chondrule matter (requiring T\(\geqslant \) 1600 K) without fully vaporizing it [9]}, [10]}. But the community is divided on whether these heat blasts occurred in a `nebular' setting or a `planetary' setting [2]}, [8]}. That is, was chondrule formation a widespread phenomenon within the protoplanetary disk that preceded asteroid and planet formation, or a much smaller scale phenomenon associated with the late stages of planetesimal formation? In the first case, one might expect primitive asteroids to be as full of chondrules as chondrites are. In the second, chondrules may be rare or absent on many such objects.
